He is credited with being the 'architect of devolution' in Wales and led the campaign to create the National Assembly for Wales. He became the first Cabinet Minister to resign from Tony Blair's Cabinet, in 1998, following what became known as a "moment of madness" when he was mugged at knifepoint after agreeing to go for a meal with a man he had met at the well-known gay meeting place of Clapham Common.

Davies was first elected as a Councillor in 1969 to the former Machen Urban District Council at the age of 23. A year later he became the youngest council leader in Britain at the age of 24. After local government re-organisation in 1974 he continued as leader of the newly constituted Rhymney Valley District Council and led a campaign for a Fair Rents Act against plans by the Conservative Government of Edward Heath to increase the amount of rent paid by Council house tenants, although in Labour circles it was well known that he wanted to surrender to the government, but was voted down by the local labour party management, led by Ray Davies.

After training to be a teacher at Cardiff University he spent two years as a school teacher before becoming a Tutor-Organiser for the Workers' Educational Association, succeeding Neil Kinnock in 1970 when the future Labour leader was elected to Parliament. He went on to become Further Education Adviser for the Mid-Glamorgan Education Authority from 1974 until 1983, when he was elected to Parliament as the Labour MP for Caerphilly.

After two years as a backbench MP, Ron Davies was appointed an Opposition Whip in 1985, where his subject areas included agriculture and the environment. In 1987 he was appointed to the opposition frontbench as a spokesman on Agriculture and Rural Affairs responsible for reviewing the Labour Party's policies on animal welfare.

As the Labour Party's chief spokesman for Wales from 1992 to 1997, Ron Davies developed the party's devolution policy. He negotiated support for a sixty-member Welsh Assembly to take over the functions of the Secretary of State for Wales and elected by an element of proportionality. His personal preference for a body with stronger powers was defeated internally.

In May 1997 Ron Davies was appointed by Tony Blair to the Privy Council and the Cabinet as Secretary of State for Wales. One of his first acts was to return the £150,000 to the Aberfan disaster fund that a previous Labour Government had taken to restore the site of the landslide that had devastated the valley's community in 1966, although controversially this was without interest being paid. As over thirty years had passed, the money was worth a fraction of its original value.

In July 1997, he published the Government's detailed devolution proposals in the White Paper "A Voice for Wales" and led the Labour Party's successful campaign for a 'yes' vote in the devolution referendum on 18 September 1997. Though Labour reversed a 4 to 1 majority against devolution recorded in the 1979 referendum, the slender majority of 0.6% on a 50.1% turnout, cast a shadow over the institution's authority.

He has been credited with being "the architect of devolution", and was appointed to the highest order of the Gorsedd of the Bards at the 1998 National Eisteddfod in Bridgend, earning the bardic name "Ron o Fachen" (Ron from Machen)

On 19 September 1998, he defeated Rhodri Morgan to become Labour's candidate for First Secretary of the Assembly at a special Welsh Labour Party conference in Newport. Just over a month later on 29 October 1998, he resigned this post - two days after resigning as Secretary of State for Wales on 27 October 1998. He stood down citing "an error of judgment" in agreeing to go for what he said was a meal with a man he had met while walking on Clapham Common in London, which is a well-known gay meeting place. He was mugged at knifepoint. The full details of the incident (which he infamously called a "moment of madness" at the urging of Tony Blair's Press SecretaryAlastair Campbell) have never emerged.[3] He later acknowledged that he was bisexual, and was receiving treatment for a personality disorder which led him to seek out risky situations.[4] He stood down from Parliament at the 2001 general election.

On 30 January 1999, Ron Davies was selected as a Labour candidate for the first elections to the National Assembly for Wales. He was elected on 6 May 1999 as Assembly Member for the Caerphilly Constituency, and initially chaired the Economic Development Committee after Alun Michael refused to appoint him to his Cabinet. Further revelations and disagreements with the Labour leadership resulted in his resignation from the Chairmanship of the committee.

He is known for the phrase "Devolution is a process and not an event", by which he meant that the settlement he introduced in 1997 would not be the final one, and more powers would accrue to the Welsh Assembly over time. He wrote a pamphlet for the think tank the Institute of Welsh Affairs with the same title in 1998.

Shortly before the 2003 assembly elections, The Sun revealed that Davies had been visiting a well-known cruising spot near a motorway lay-by. When challenged as to what he had been doing there, Davies initially denied being there, then told reporters that he had been going for a short walk, adding: "I have actually been there when I have been watching badgers".[5] Davies was forced to stand down as Labour candidate in the election.

Davies was elected as an independent councillor for Bedwas, Trethomas and Machen in May 2008 and was the Cabinet Member for Regeneration.[9] In 2012 he stood as a Plaid Cymru candidate for Bedwas, and was defeated.[12]